I started out with crocs and found them to become very flat and unsupportive after around a month. i switched to Dansko clogs around that time and have never regretted it. They take a while to get used to, but it is worth it. If you go with those, it's important to know that your heel is supposed to come up off the sole of the shoe. I had lower back and shoulder pain before i started wearing them, and they must do something for my posture because the pain has resolved itself without PT or anything since wearing those clogs! Also, my feet hardly ever hurt and never cramp with the clogs. and this is on 9hour clinical days
In the hospital i see mostly sneakers, but they are hard to clean (and you can only imagine what gets on them) unless you get 100% leather.
In our program our shoes have to be all white and have backs on them so I decided that I wanted a clog-type shoe for clinicals. I used to be a teacher and I knew that even wearing tennis shoes after a long day of standing can be painful so I opted for the 'dorky' typical nursing shoes. I liked the dansko clogs but the lady at the med shop told me they take a while to break into and I didn't have that time so I went with the 'Klogs' brand of clogs...they have been great...no complaints, and this is my 4th semester wearing them
I have some New Balance walking shoes. Tried some Cherokee "nursing" shoes first semester and they were wretched. After graduation I think I might get some Timberland Pro Renovas. I tried them once and they were lovely.
Leather tennis shoes with good arch support. I especially like the K-Swiss brand. Usually can find them on sale.
Any well-constructed leather cross-training or walking shoes will also work. Nike, Reebok, and Addidas are also good brands. Go to a big box shoe retailer and find a pair or two that you like (if you need all-white, the selection will be better at a bigger store).
I can't wear any kind of "athletic" shoe for long term standing because they kill my feet. I tried on a pair of my classmates Danskos and it was horrible, like standing on concrete. I tried Shape Ups and they made my knees throb. I absolutely hate K Swiss shoes and I found Nike Shox to be incredibly UNcomfortable. I love Crocs myself and for clinical I wear Crocs Saffron in white leather. I love them.
But, as you can see, its not really helpful to get shoe advice from others because we're all different. The shoes others have loved, I hate. And I'm sure the opposite is true as well. So, the best thing to do is to try various shoes for yourself.